A cerium oxide (ceria) is a semiconductor generally known as an important material due to a catalytic property and having a wide band gap. Ceria has been extensively used as a catalyst, for example, for fluid cracking, harmful gas purification, a solid oxide fuel cell, an antioxidant in biological medicine, or an abrasive for chemical mechanical planarization (CMP) process in a micro-electronics industry. In addition, as generally known to in the art, the performance of the ceria is closely related to the shape and the structural arrangement of a ceria crystal. When ceria has the shape of a thin film, the ceria has a high refractive index, a high dielectric constant, and a lattice constant similar to that of Si. Accordingly, the ceria may be employed in technologies related to Si, such as micro-electronics and optics. The nano-size ceria represents improved activity because of an increased surface area, a surface superoxide, and the easier formation of an air gap between oxygen atoms.
Recently, ceria nano-particles have significantly attracted attention as an agent to prevent cells from being aged. Brain cell cultures containing ceria nano-particles are improved in lifespan. The mechanism connected with the lifespan is associated with free radical scavenging from cells so that the damage to the cells may be eliminated or reduced. According to the effect of the free radical scavenging, Ce3+ reduces free radicals, and is oxidized to Ce4+. Since the ceria nano-particles having high reactivity may be applied to various fields, there have been reported various manners, such as sol-gel and solvothermal routes, sonochemical, coordination chemistry, and pyrolysis methods, that prepare ceria nano-particles.
However, pure ceria nano-particles have low thermal stability under an oxidation condition and a sintering atmosphere, which affects the performance of the ceria nano-particles. Accordingly, there are required studies and researches on structures of maximizing advantages of a support and ceria nano-particles by combining the ceria nano-particles and a support materials to maintain the large surface area and the high activity of the ceria nano-particles even under high temperature and inferior environments.
As the related art, there is disclosed Korean Unexamined Patent Publication No. 10-2012-0125999 (published on Nov. 20, 2012) entitled “Method of Preparing Silica-Ceria, Core-Shell Nano-Particles Using Microemulsion”.